[Bug Report][2.6.7] VItemGroup does not correctly use valueComparator

[hrobertson]

Environment

Vuetify Version: 2.6.7
Vue Version: 2.7.3
Browsers: Chrome 103.0.5060.53
OS: Linux x86_64

Steps to reproduce

1. Use a V-Item-Group with object values or a custom valueComparator, or both.
2. Observe that the active state of items is correct, but the value does not get updated correctly.

Expected Behavior

Model value is updated according to the valueComparator

Actual Behavior

Model value is updated according to exact equality.

Reproduction Link

https://codepen.io/hrobertson/pen/ExEPLGd

Other comments

#14328 only did half the job - Only the toggleMethod function was updated to use the valueComparator and this is only used for determining the active state, not for determining how the model value should be updated.